1. NHANES Data (US National Health Survey, 2007-2021)

• Found 40-44% of US adults aged 18-44 are insulin resistant using HOMA-IR measurements
• Most commonly cited source for the “40%” prevalence figure
• Prevalence has remained consistently high across multiple survey periods

2. Global Meta-Analysis (2025)

• Analyzed 86 studies from 2001-2024 across multiple countries
• Found overall global IR prevalence of 26.53%, but this varied widely by geographic region and cutoff used

The Critical Cutoff Problem:

Why “40-50% (higher with proper cutoffs)”? Most studies use HOMA-IR cutoffs of 2.5-3.0, which were derived from populations that were already metabolically unhealthy. This creates circular logic—defining “normal” based on sick populations. Different Thresholds Yield Different Results:

• Using HOMA-IR ≥2.5 (most common): Captures ~40-45%
• Using HOMA-IR ≥2.0 (conservative): Likely captures 60-65%
• Using HOMA-IR ≥1.9 (Qatar study optimal cutoff): Likely captures 70-75%+
• Using truly healthy populations as reference: Possibly 80-90% in Western societies

Qatar Study (2025) found the optimal cutoff at HOMA-IR 1.878—far lower than the commonly used 2.5 threshold. Using this more accurate threshold would identify significantly more people with early insulin resistance.

Why We Use “40-50% (higher with proper cutoffs)”:

The 40-50% range is:

• Well-documented in peer-reviewed NHANES studies
• Conservative and defensible
• Based on widely accepted (though lenient) cutoff of ≥2.5

The “higher with proper cutoffs” caveat acknowledges:

• The 2.5 threshold is probably too lenient
• Using more stringent cutoffs (1.9-2.0) reveals higher true prevalence
• Actual prevalence in Western populations is likely 60%+ and possibly much higher

The Bottom Line:

Even using conservative estimates (HOMA-IR ≥2.5), nearly half of Western adults have insulin resistance. Using optimal cutoffs based on truly healthy populations (HOMA-IR ≥1.9), the majority likely have some degree of insulin resistance—making it the predominant metabolic condition in modern society. This version removes redundancy while preserving all the key evidence and reasoning. Does this work better?